Hydraulic aggregate for the leakage cavity of a pump

ABSTRACT

The present invention relates to a hydraulic aggregate for a hydraulic controlling and/or regulating device, including a pump having a pump housing that includes a leakage chamber with a leakage bore opening into a hollow space of a lid fixed to the pump housing, said hollow space having a pressure-fluid connection to the atmosphere. The leakage bore is connected to the atmosphere by way of a float valve open in its basic position, and the float valve effects closure of the leakage bore under the effect of hydrostatic pressure in lid.

[0001] The present invention relates to a hydraulic aggregate for a hydraulic controlling and/or regulating device according to the preamble of claim 1.

[0002] DE 198 51 762 A1 discloses a hydraulic aggregate of the type mentioned hereinabove. The hydraulic aggregate includes a pump having a leakage chamber that is permanently connected to a hollow space of a lid by way of a pipe in a leakage bore. Under unfavorable operating conditions of the hydraulic aggregate, this arrangement does not always ensure functionally proper ventilation and venting or a functionally proper leakage discharge of the pump out of the leakage chamber into the hollow space of the lid. In addition, the pipe is subject to very close manufacturing tolerances, especially when the opening of the pipe has a small design, which may lead to blocking of the pipe passage.

[0003] Therefore, an object of the present invention is to improve upon a hydraulic aggregate of the generic type in such a way as to avoid the above-mentioned shortcomings.

[0004] According to the present invention, this object is achieved for a hydraulic aggregate of the above-mentioned type by way of the characterizing features of patent claim 1.

[0005] Further features, advantages and possible applications of the present invention can be taken in the following from the description of an embodiment making reference to several accompanying drawings.

[0006] In the drawings,

[0007]FIG. 1 is a sectional view of the relevant components for a hydraulic aggregate.

[0008]FIG. 2 is a partial view of the hydraulic aggregate according to FIG. 1 in the closing function of the float valve of the invention.

[0009]FIG. 3 is a partial view of the hydraulic aggregate according to FIG. 1 in the partially open position of the float valve.

[0010]FIG. 4a is an enlarged cross-sectional side view of a valve sleeve.

[0011]FIG. 4b is a top view of the valve sleeve.

[0012]FIG. 1 shows the principal illustration of a hydraulic aggregate for a hydraulic controlling and/or regulating device, including a pump with a pump housing 12 that has a leakage chamber 8 with a leakage bore 1 opening into a hollow space 6 of a lid 3 fixed to the pump housing 12, said hollow space having a pressure-fluid connection 13 to the atmosphere. According to the invention, the leakage bore 1 includes a float valve 2, which either effects ventilation under atmospheric pressure in lid 3 or closure of the leakage bore 1 under the effect of a hydrostatic pressure in lid 3. In the illustration shown the float valve 2 is in its open position under the effect of gravity, the arrangement of the hydraulic aggregate as depicted contributing to this end. In detail, the hydraulic aggregate includes a block-shaped pump housing 12 into which an electric motor with an eccentric is fitted from above, said electric motor being used to drive a plurality of pump pistons (not shown in the drawing) in the pump housing 12. Thus, the leakage chamber 8 generally corresponds to the crank chamber for receiving the pump drive. Succeeding at the bottom of the leakage chamber 8 in the direction of the lid 3 is the leakage bore 1 in the form of a through-bore. Consequently, lid 3 is disposed below the block-shaped pump housing 12. Ventilation and venting of the hollow space 6 and the leakage chamber 8 is ensured by way of the lateral pressure fluid connection 13 disposed at the deepest point of lid 3, to what end the float valve 2 in the open position, due to its weight, is supported on the elevated inside wall of lid 3. This illustrated position of the float valve 2 not only permits unimpeded ventilation and venting of the hollow spaces (leakage chamber 8, hollow space 6) being interconnected due to the generously sized radial distance between the tubular socket 5 and the valve sleeve 4 of the float valve 2 slidable herein. It additionally allows unimpeded passage of the pump fluid out of the leakage chamber 8 into the hollow space 6 of lid 3 so that the possibly existing pump leakage due to the effect of gravity may propagate along the inside wall of the lid 3 to the lateral pressure fluid connection 13 and from there may be discharged out of lid 3, if so required. This renders an exchange of fluid and gas along the periphery of the float valve 2 possible at any time, as long as the float valve 2 keeps assuming the open position according to the drawing. On the other hand, the function of the through-opening in the valve sleeve 4 is exclusively limited to the exchange of gas between the hollow space 6 and the leakage chamber 8 because a fluid-impermeable diaphragm 11 is fitted to valve sleeve 4, what will be dealt with in the description of the float valve 2 according to FIGS. 4a, 4 b.

[0013] According to the drawing, lid 3 is flanged from below to the frontal end of pump housing 12. If required, lid 3 accommodates electrical and/or electronic controlling and regulating elements for operating the electric motor and, if required, for operating several solenoid valves arranged in the pump housing 12.

[0014] Different from the open position of the float valve 2 of FIG. 1, FIG. 2 now shows the closed position of the float valve 2 because the hydraulic unit is in an immersed situation where water has entered through the pressure fluid connection 13 into the hollow space 6 of lid 3. Under the effect of the hydrostatic buoyancy at the float valve 12, the annular seal 10 arranged between the tubular socket 5 and the collar 9 at float valve 2 closes the slot (leakage channel 7 in FIGS. 4a, 4 b) disposed between the tubular socket 5 and the valve sleeve 4 in a fluid-tight fashion.

[0015] Due to the valve construction chosen, an air bubble 14 simultaneously remains inside the float valve 2 and assists the closing movement of the float valve 2. The air bubble 14 in the float valve 2 is disposed between the water level and the diaphragm 11 fitted at the frontal end of the float valve 2. When the hydraulic aggregate cools down, the air volume in the leakage chamber 8 experiences a vacuum effect, since the diaphragm wetted by water prevents pressure balance. Consequently, the float valve 2 remains without change in the desired closed position until the immersion action is terminated.

[0016]FIG. 3 shows the float valve 2 at the beginning of opening when, after termination of the immersion action, the water in the hollow space 6 is able to exit again to the atmosphere through the pressure fluid connection 13, whereby the hydrostatic buoyancy at the float valve 2 collapses. The subsequently dominating weight of the float valve 2 again offers the possibility of discharging the pump leakage out of the leakage chamber 8 through the peripheral leakage channel 7 in the direction of the hollow space 6, while additionally an exchange of gas can take place via the diaphragm 11 between the leakage chamber 8 or the adjoining housing of the electric motor and the atmosphere. With a decreasing fluid level in the hollow space 6, the valve sleeve 4 due to the effect of gravity and, as the case may be, additionally due to vibrations of the hydraulic aggregate, will move into the fully opened valve position, which can already be taken from the illustration of FIG. 1.

[0017] Based on the preceding explanations, FIG. 4a shows an enlarged side view of the valve sleeve 4 that is preferably made up of a particularly light material, e.g. of polypropylene, on the surface whereof a disc-shaped diaphragm 11 is arranged. Said diaphragm is permeable to gas, but prevents the exchange of fluid, and it is preferably welded to the valve sleeve 4. What can be easily seen in this side view are the leakage channels 7 that extend on either side of the valve sleeve member similar to a longitudinal groove. Adjacent to channels 7 is an annular seal 10 that is carried by a collar 9 shaped below the tubular portion in the way of a seat valve.

[0018] Based on FIG. 4a, FIG. 4b shows the top view of the valve sleeve 4 from which the square outside profile of the valve sleeve 4 becomes clearly apparent, permitting an unhindered gas exchange and fluid discharge in the open position of the float valve 2. The diaphragm 11 illustrated as net or mesh can be seen coaxially to the cross-section of the valve sleeve 4 (e.g. ‘Goretex’ diaphragm), while the annular seal 10 is retained at collar 9.

[0019] Thus, the present invention describes an automatic float valve 2 ensuring in its normally open position the ventilation of the electric motor and the unimpeded leakage discharge out of the leakage chamber 8 of the pump. In the case of an immersion situation, the float valve 2 closes automatically and, hence, situation, the float valve 2 closes automatically and, hence, prevents the ingress of water into the leakage chamber 8 and into the electric motor. The use of the gas-permeable diaphragm 11 shall be noted which, after the immersion situation, renders possible a pressure balance between the inside chamber of the electric motor and the atmosphere. The pressure balance is the condition for an automatic opening of the float valve 2.

[0020] A particularly simple construction is achieved for the float valve 2 when it is configured as a valve sleeve 4 arranged in a tubular socket 5 slidable in the leakage bore 1, with sections of said tubular socket 5 extending into the hollow space 6 of the cover 3. Between the tubular socket 5 and the valve sleeve 4 at least one leakage channel 7 is necessary which discharges leakage fluid out of the leakage chamber 8 of the pump into the hollow space 6 of the lid 3 when the float valve 2 adopts its open position.

[0021] A manufacture of several leakage channels 7, which is especially favorable under the aspects of construction, is possible when the valve sleeve 4 is designed as square outside profile whose end portion passes over into a collar 9 at which the annular seal 10 is arranged to form a valve seat. The annular seal closes the tubular socket 5 and, thus, the leakage channels 7 under the effect of the hydrostatic lifting force.

[0022] As mentioned already, the end of the valve sleeve 4 remote from the collar 9 has a special significance because it receives the gas-permeable but fluid-impermeable diaphragm 11 separating the leakage chamber 8 in the pump housing in a fluid-tight manner from hollow space 6 and lid 3 when the float valve 2 assumes its closed position.

[0023] The construction presented hereinabove renders it possible that the tubular socket 5 with the float valve 2 forms a pre-assembled and pre-adjusted, independently operable assembly having sections of tubular socket 5 pressed by a defined standard into the leakage bore 1 for the purpose of adjusting the float valve 2.

[0024] Under construction aspects care must be taken that an axial distance is provided between the tubular socket 5 and the inside wall of the lid 3 which is at least as large as the working stroke of the float valve 2, said float valve 2, in its open position, being supported with its collar 9 on the inside wall of lid 3. List of Reference Numerals 1 leakage bore 2 pump housing 3 lid 4 valve sleeve 5 tubular socket 6 hollow space 7 leakage channel 8 leakage chamber 9 collar 10 annular seal 11 diaphragm 12 pump housing 13 pressure fluid connection 14 air bubble 

1. Hydraulic aggregate for a hydraulic controlling and/or regulating device, including a pump having a pump housing that includes a leakage chamber with a leakage bore opening into a hollow space of a lid fixed to the pump housing, said hollow space having a pressure-fluid connection to the atmosphere, characterized in that the leakage bore (1) is connected to the atmosphere by way of a float valve (2) open in its basic position, and in that the float valve (2) effects closure of the leakage bore (1) under the effect of hydrostatic pressure in lid (3).
 2. Hydraulic aggregate as claimed in claim 1, characterized in that the float valve (2) comprises a valve sleeve (4) which is slidably arranged in a tubular socket (5) that is inserted into the leakage bore (1) and extends into the hollow space (6) of the lid (3).
 3. Hydraulic aggregate as claimed in claim 1 or 2, characterized in that at least one leakage channel (7) is interposed between the tubular socket (5) and the valve sleeve (4), said leakage channel allowing leakage fluid out of the leakage chamber (8) of the pump to propagate into the hollow space (6) of lid (3) when the float valve (2) adopts its open position.
 4. Hydraulic aggregate as claimed in any one of the preceding claims, characterized in that for forming several leakage channels (7) the valve sleeve (4) includes a square outside profile having an end that includes a collar (9) whereat an annular seal (10) is arranged for forming a valve seat, said seal (10) abutting on the tubular socket (5) and closing the leakage channel (7) under the effect of hydrostatic pressure.
 5. Hydraulic aggregate as claimed in claim 4, characterized in that the end of the valve sleeve (4) remote from the collar (9) has a gas-permeable, but fluid-impermeable diaphragm (11) that fluid-tightly isolates the leakage chamber (8) in the pump housing from the hollow space (6) in lid (3) when the float valve adopts its closed position.
 6. Hydraulic aggregate as claimed in any one of the preceding claims, characterized in that the tubular socket (5) in conjunction with the float valve (2) forms a pre-assembled and pre-adjusted independently operable assembly, with sections of the tubular socket (5) being pressed into the leakage bore (1) for the purpose of adjusting the float valve (2).
 7. Hydraulic aggregate as claimed in any one of the preceding claims 1 to 6, characterized in that there is an axial distance between the tubular socket (5) and the inside wall of the lid (3) which is at least as large as the working stroke of the float valve (2), the said float valve (2) in its open position being supported with its collar (9) on the inside wall of the lid (3). 